5. Execute Experiment

5.1 Send IP traffic

The first simple experiment that we will run is to verify the IP connectivity between our hosts.

Check the interfaces of your nodes. In the terminal type:

sudo ifconfig

You should see at least two interfaces:

The control interface. This is the interface you use to access the node, e.g. ssh into your host. The control interface is mainly used for control traffic, i.e. traffic for controlling the node and the experiment.

The data interface. This is the interface that is used for sending experimental traffic. This is the interface that connects to the other hosts of your experiment through GENI. The links between these interfaces are the ones that allow you to run non-IP experiments. The data interface is the one that has an IP address and mask that match what you configured before you reserved your resources.

Fill in the worksheet, noting the name and IP address of the control and of the data interfaces for each node.

The command prompt on each node says "client" or "server" respectively.

From the client, ping the server. From the terminal window that is logged in to the client type :

5.2 (optional) Send non-IP traffic

Doing this step requires that you did step 4.2 above.

GENI provides the capability of running non-IP experiments, since you can connect your hosts at Layer 2. For the purpose of this tutorial we will use a very simple Layer 2 ping program that sends packets using a custom ethernet type.

ExoGENI nodes run a service called "neuca" that managed network interfaces on the node. To manually adjust the IP address, we must first disable neuca on both nodes.

sudo service neuca stop

The ExoGENI "neuca" service controls a variety of network configuration details.

Disable the IP on both of your nodes (being careful to disable IP on the data interface NOT the control interface).
In each of the terminals type:

sudo ifconfig <data interface name> 0.0.0.0

Be extra careful to disable the IP on the data interface, bringing down the IP on the control interface means that you will lose connectivity to your host.

Try again to ping from the client to the server. In the terminal window of the client type:

ping <server data IP addr> -c 5

For example:

ping 10.17.1.2 -c 5

This time the ping should indicate that the destination is unreachable.

Start the Layer 2 ping server. In the server terminal window, type:

sudo ~/pingPlus-0.2/pingPlusListener <EtherType from worksheet>

From the client try to ping the server at layer 2. You will need the mac address of the data interface of the server, the name of the data interface of the client, and the EtherType from your worksheet. In the terminal window of the client, type: